An imager module includes at least a lens and an image sensor. An image detected by the image sensor is displayed on a display. Typically, the image sensor has three types of detector elements, each element providing a color intensity value for a primary color (e.g., one of red (R), green (G), and blue (B)) and accordingly the sensor provides R, G, and B individual color images to the display, each individual color image being a composite of pixels that have color intensity values for each of the colors.
In some circumstances, the lens has chromatic aberration resulting in differences in the primary color pixels. Accordingly, individual R, G, and B color images formed by the lens are not on the same focal plane. If the position of the image sensor is adjusted to optimize the R image, the detected R image will be sharp while the detected G and B images are not.
To make all R, G, and B images sharp, the detected R, G, and B images are sometimes processed and electronically restored before they are forwarded to the display. Various methods are used to correct the less sharp images using information gained from the sharpest image. It is appreciated that some methods attempt to find the sharpest image (among R, G, and B) in order to restore the images which are less sharp. In general, these methods relate to cross-color image processing for sharpness enhancement.
In the existing art, these cross-color image processing methods are complicated and not always accurate. For example, depending on the distance of the object to the imager, the sharpest image among R, G, and B can vary. That is, in a single image, the sharpest individual color image (R, G, or B) for near objects differs from the sharpest individual color image (R, G, or B) for far objects; thus a single sharpest individual color image (R, G, or B) in a single composite color image cannot be defined. Although certain cross-color image processing difficulties may be solved using alternative approaches—for example, by partitioning the image into several regions—a long computational process results.